Property and Equipment, Net (Property and Equipment, Net (Including Assets Held Under Capital Leases)) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 5,644,307	$ 5,491,126
Less: accumulated depreciation	(2,856,593)	(2,678,780)
Property and equipment, net	2,787,714	2,812,346
Towers and Related Components [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	4,897,273	4,772,807
Construction-In-Process [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	35,336	34,689
Furniture, equipment and vehicles [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	54,880	53,260
Land, Buildings and Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 656,818	$ 630,370